1. Field of the Invention
The present invention relates to a mask assembly for a Cathode Ray Tube (CRT), and more particularly, to a mask assembly for a CRT which can minimize the transference of vibration through a frame.
2. Description of the Related Art
Generally, a Cathode Ray Tube (CRT) is an electronic tube where electron beams emitted from an electron gun are deflected due to a magnetic deflection field, pass through a color selection shadow mask, and then strike and excite green, blue, and red phosphors on a phosphor screen within a panel, thereby displaying desired images.
In the CRT, the mask assembly comprises a shadow mask and a frame which is the supporting body of the shadow mask.
The shadow mask is formed such a way that a plurality of beam passage holes are formed on a metal plate through a photolithography process, and the circumference of the frame is bent through a pressing process. The frame is fixed to the circumference of the shadow mask through a method such as welding.
A plurality of spring members are attached on the outer circumference portion of the frame, and the mask assembly is built in a CRT in such a way that the spring members are inserted into a stud pin fixed in a panel.
The shadow mask has a color selection function of selecting the emitted electron beams and landing them on the phosphor screen.
For this purpose, it is important that the beam passage holes maintain a predetermined pattern to guarantee high image quality.
Since the shadow mask is very thin and weak, transference of the vibration to the shadow mask should be minimized when shocks or vibrations due to the sound pressure of speakers are applied to the shadow mask.
To prevent the transference of the vibration, the thickness of the frame can be increased. But in this case, the weight of the mask assembly will be also increased, so another method to improve the strength while not increasing the weight of the frame is needed.